Abstract

Reconnection is an important process of structure formation in fluid dynamics. It occurs in form of vortex reconnection in hydrodynamics as well as in form of magnetic reconnection in plasmas. Two basic types of reconnection are known. The planar two-dimensional reconnection and the more generic, but more complicated three-dimensional case. These two types differ for example with respect to their production of helicity in reconnection. Simple analytic examples of vortex reconnection are given and compared with corresponding solutions of magnetic reconnection. It is shown that, while for magnetic reconnection two-dimensional stationary solutions exist, vortex reconnection always requires a time-dependent velocity field. This explains why vortex reconnection in spite of all similarities often has a more complicated geometry than magnetic reconnection.